I have a Wren concertina fron McNeela in Ireland. I have had it about two years. Not long after I got it one key would sometimes stick open. In 2018 I was in the hospital for 101 days and in bed about 6 months. When I finally felt like playing my concertina had about 5 buttons sticking. When some buttons are pressed, they catch other buttons and open them as well. Does anyone have any advice? i am fairly handy with tools, but don’t know what the insides looks like. The Wren has good reviews, I have not been happy with mine.